vfs: document ->d_real()

[deliverable/linux.git] / include / linux / dcache.h

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 484c8792da825ed27bc17485fa3b4807e60d745f..14df83609c7ff22634e35b7c028c554cf7d9b952 100644 (file)
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -139,8 +139,8 @@ struct dentry_operations {
        char *(*d_dname)(struct dentry *, char *, int);
        struct vfsmount *(*d_automount)(struct path *);
        int (*d_manage)(struct dentry *, bool);
-       struct inode *(*d_select_inode)(struct dentry *, unsigned);
-       struct dentry *(*d_real)(struct dentry *, struct inode *);
+       struct dentry *(*d_real)(struct dentry *, const struct inode *,
+                                unsigned int);
 } ____cacheline_aligned;
 
 /*
@@ -206,12 +206,11 @@ struct dentry_operations {
 
 #define DCACHE_MAY_FREE                        0x00800000
 #define DCACHE_FALLTHRU                        0x01000000 /* Fall through to lower layer */
-#define DCACHE_OP_SELECT_INODE         0x02000000 /* Unioned entry: dcache op selects inode */
-
-#define DCACHE_ENCRYPTED_WITH_KEY      0x04000000 /* dir is encrypted with a valid key */
-#define DCACHE_OP_REAL                 0x08000000
+#define DCACHE_ENCRYPTED_WITH_KEY      0x02000000 /* dir is encrypted with a valid key */
+#define DCACHE_OP_REAL                 0x04000000
 
 #define DCACHE_PAR_LOOKUP              0x10000000 /* being looked up (with parent locked shared) */
+#define DCACHE_DENTRY_CURSOR           0x20000000
 
 extern seqlock_t rename_lock;
 
@@ -556,23 +555,37 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
        return upper;
 }
 
-static inline struct dentry *d_real(struct dentry *dentry)
+/**
+ * d_real - Return the real dentry
+ * @dentry: the dentry to query
+ * @inode: inode to select the dentry from multiple layers (can be NULL)
+ * @flags: open flags to control copy-up behavior
+ *
+ * If dentry is on an union/overlay, then return the underlying, real dentry.
+ * Otherwise return the dentry itself.
+ *
+ * See also: Documentation/filesystems/vfs.txt
+ */
+static inline struct dentry *d_real(struct dentry *dentry,
+                                   const struct inode *inode,
+                                   unsigned int flags)
 {
        if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
-               return dentry->d_op->d_real(dentry, NULL);
+               return dentry->d_op->d_real(dentry, inode, flags);
        else
                return dentry;
 }
 
-static inline struct inode *vfs_select_inode(struct dentry *dentry,
-                                            unsigned open_flags)
+/**
+ * d_real_inode - Return the real inode
+ * @dentry: The dentry to query
+ *
+ * If dentry is on an union/overlay, then return the underlying, real inode.
+ * Otherwise return d_inode().
+ */
+static inline struct inode *d_real_inode(struct dentry *dentry)
 {
-       struct inode *inode = d_inode(dentry);
-
-       if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE))
-               inode = dentry->d_op->d_select_inode(dentry, open_flags);
-
-       return inode;
+       return d_backing_inode(d_real(dentry, NULL, 0));
 }